Touch display device, driving method, and driving circuit

ABSTRACT

Embodiments of the present disclosure relate to a touch display device, a driving method, and a driving circuit. More particularly, embodiments of the present disclosure relate to a touch display device, a driving method, and a driving circuit capable of preventing touch sensitivity from being affected by display driving even though simultaneously performing the display driving and touch driving by supplying a data voltage to a plurality of data lines disposed in a display panel, supplying a common voltage to a plurality of common electrodes disposed in the display panel, displaying an image through the display panel, and supplying a common voltage to the common electrodes.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Republic of Korea PatentApplication No. 10-2017-0108889 filed on Aug. 28, 2017 and Republic ofKorea Patent Application No. 10-2017-0174260 filed on Dec. 18, 2017,each of which is hereby incorporated by reference in its entirety.

BACKGROUND 1. Field of Technology

The present disclosure relates to a touch display device, a drivingmethod, and a driving circuit.

2. Description of the Prior Art

As a society develops into an information society, there is increasingdemand for various types of display devices for displaying images. Inrecent years, various display devices such as a liquid crystal displaydevice, a plasma display device, and an organic light-emitting diodedisplay device have been utilized.

Among such display devices, there is a touch display device capable ofproviding a touch-based input method that enables a user to easily inputinformation or a command intuitively and conveniently, breaking from theconventional input methods using a button, a keyboard, a mouse, etc.

Such a touch display device should provide both an image displayfunction and a touch sensing function. Thus, the touch display devicedivides a driving time such as a frame time into a display drivingperiod and a touch driving period, performs display driving in thedisplay driving period, and performs touch driving and touch sensing inthe touch driving period subsequent to the display driving period.

In the case of the above-described time division driving method, inorder to perform the display driving and the touch driving in a timedivision manner, a very precise timing control is required and expensivecomponents for this may be required.

In addition, the time division driving method has a problem in thatsince both the display driving time and the touch driving time may beinsufficient, both the image quality and the touch sensitivity aredeteriorated. In particular, there is a problem in that high-resolutionimage quality cannot be provided due to time division driving.

SUMMARY

In view of the foregoing, embodiments of the present disclosure are toprovide a touch display device, a driving method, and a driving circuitcapable of simultaneously performing display driving and touch driving.

Also, embodiments of the present disclosure are to provide a touchdisplay device, a driving method, and a driving circuit that preventtouch sensitivity from being affected by display driving.

Further, embodiments of the present disclosure are to provide a touchdisplay device, a driving method, and a driving circuit capable ofperforming touch sensing without being affected by data driving.

Further, embodiments of the present disclosure are to provide a touchdisplay device, a driving method, and a driving circuit capable ofpreventing touch sensing from being disabled or a touch sensitivity frombeing deteriorated even if a voltage state of a data voltage is changed.

Moreover, embodiments of the present disclosure are to provide a touchdisplay device, a driving method, and a driving circuit capable ofpreventing touch sensing from being disabled or a touch sensitivity frombeing deteriorated in a specific display pattern.

Also, embodiments of the present disclosure are to provide a touchdisplay device, a driving method, and a driving circuit, which cansimultaneously perform display driving and touch driving whilepreventing the occurrence of a display touch crosstalk includingdistortion of a touch-related signal by display driving.

Embodiments of the present disclosure may provide a touch display devicecomprising: a display panel including a plurality of data lines, aplurality of gate lines, a plurality of sub-pixels defined by theplurality of data lines and the plurality of gate lines, and a pluralityof common electrodes; a first circuit configured to supply a datavoltage to the plurality of data lines, supply a common voltage thatalternates between a first common voltage level and a second commonvoltage level that is greater than the first common voltage level to theplurality of common electrodes, and detect a signal from at least one ofthe plurality of common electrodes, wherein the common voltage changesfrom the first common voltage level to the second common voltage levelat a predetermined time after the data voltage changes from a first datavoltage level to a second data voltage level that is greater than thefirst data voltage level or at a predetermined time after a datasynchronous signal that is synchronized with the data voltage changesfrom a first signal level to a second signal level that is less than thefirst signal level; and a second circuit configured to sense a touchbased on a signal detected by the first circuit.

In one embodiment, a method of driving a touch display device comprisinga display panel that includes a plurality of data lines, a plurality ofgate lines, a plurality of sub-pixels defined by the plurality of datalines and the plurality of gate lines, and a plurality of commonelectrodes, the method comprises: supplying a data voltage to theplurality of data lines; supplying a common voltage that alternatesbetween a first common voltage level and a second common voltage levelthat is greater than the first common voltage level to the plurality ofcommon electrodes, wherein the common voltage changes from the firstcommon voltage level to the second common voltage level at apredetermined time after the data voltage changes from a first datavoltage level to a second data voltage level that is greater than thefirst data voltage level or at a predetermined time after a datasynchronous signal that is synchronized with the data voltage changesfrom a first signal level to a second signal level that is less than thefirst signal level; and displaying an image through the display paneland sensing a touch based on a signal detected from at least one of theplurality of common electrodes.

In one embodiment, A driving circuit of a touch display devicecomprising a display panel including plurality of data lines, aplurality of gate lines, a plurality of sub-pixels defined by theplurality of data lines and the plurality of gate lines, and a pluralityof common electrodes, the driving circuit comprises: a first drivingcircuit configured to supply a data voltage to the plurality of datalines; and a second driving circuit configured to supply a commonvoltage that alternates between a first common voltage level and asecond common voltage level that is greater than the first commonvoltage level to the plurality of common electrodes, and detect a signalfor touch sensing from at least one of the plurality of commonelectrodes; wherein the common voltage changes from the first commonvoltage level to the second common voltage level at a predetermined timeafter the data voltage changes from a first data voltage level to asecond data voltage level that is greater than the first data voltagelevel or at a predetermined time after a data synchronous signal that issynchronized with the data voltage changes from a first signal level toa second signal level that is less than the first signal level.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the presentdisclosure will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIGS. 1 and 2 are system configuration diagrams of a touch displaydevice according to embodiments of the present disclosure;

FIG. 3 is a diagram illustrating a case in which a touch screen panel isembedded in the display panel of the touch display device according toembodiments of the present disclosure;

FIG. 4 is a diagram illustrating time-divisional driving of the touchdisplay device according to embodiments of the present disclosure;

FIG. 5 is a diagram illustrating time-free driving of the touch displaydevice according to embodiments of the present disclosure;

FIG. 6 is a diagram illustrating asynchronization between a data voltageand a common voltage during time-free driving of the touch displaydevice according to embodiments of the present disclosure;

FIG. 7 is a diagram illustrating a voltage fluctuation phenomenonoccurring in a common electrode according to a state change of a datavoltage during asynchronization between a data voltage and a commonvoltage in the touch display device according to embodiments of thepresent disclosure;

FIG. 8 is a diagram exemplifying an image pattern generating a displaytouch crosstalk according to a voltage fluctuation phenomenon at acommon voltage in the touch display device according to embodiments ofthe present disclosure;

FIG. 9 is a diagram for explaining a touch signal distortion phenomenoncaused by a display touch crosstalk according to a voltage fluctuationphenomenon at a common voltage in the touch display device according toembodiments of the present disclosure;

FIGS. 10 and 11 are diagrams illustrating synchronization between a datavoltage and a common voltage during time-free driving of the touchdisplay device according to embodiments of the present disclosure;

FIG. 12A is a diagram for explaining signal control of a common voltageduring time-free driving of the touch display device according toembodiments of the present disclosure;

FIG. 12B is a view illustrating examples of a display drive controlsignal that may be utilized as a data synchronous signal forsynchronizing a common voltage with a data voltage in the touch displaydevice according to embodiments of the present disclosure;

FIG. 13 is a diagram illustrating two ground voltages and a groundmodulation circuit for using the ground voltages in the touch displaydevice according to embodiments of the present disclosure;

FIG. 14 is a diagram illustrating a ground modulation circuit in thetouch display device according to embodiments of the present disclosure;

FIG. 15 is a diagram illustrating a configuration for performing aground modulation function for data synchronization of a common voltagewhich is a touch driving signal in the touch display device according toembodiments of the present disclosure;

FIG. 16 is an exemplary diagram of a power supply separation circuit inthe touch display device according to embodiments of the presentdisclosure; and

FIG. 17 is a flowchart of a method of driving the touch display deviceaccording to embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, some embodiments of the present disclosure will bedescribed in detail with reference to the accompanying illustrativedrawings. In designating elements of the drawings by reference numerals,the same elements will be designated by the same reference numeralsalthough they are shown in different drawings. Further, in the followingdescription of the present disclosure, a detailed description of knownfunctions and configurations incorporated herein will be omitted when itmay make the subject matter of the present disclosure rather unclear.

In addition, terms, such as first, second, A, B, (a), (b) or the likemay be used herein when describing components of the present disclosure.Each of these terminologies is not used to define an essence, order orsequence of a corresponding component but used merely to distinguish thecorresponding component from other component(s). In the case that it isdescribed that a certain structural element “is connected to”, “iscoupled to”, or “is in contact with” another structural element, itshould be interpreted that another structural element may “be connectedto”, “be coupled to”, or “be in contact with” the structural elements aswell as that the certain structural element is directly connected to oris in direct contact with another structural element.

FIGS. 1 and 2 are system configuration diagrams of a touch displaydevice according to embodiments of the present disclosure.

A touch display device according to embodiments of the presentdisclosure is capable of performing an image display function and atouch sensing function (touch input function).

Hereinafter, configurations for providing an image display function ofthe touch display device according to embodiments of the presentdisclosure will be described with reference to FIG. 1, andconfigurations for providing the touch sensing function (touch inputfunction) of the touch display device according to embodiments of thepresent disclosure will be described with reference to FIG. 2.

Referring to FIG. 1, the touch display device according to embodimentsof the present disclosure includes: a display panel DISP, on which aplurality of data lines DL and a plurality of gate lines GL are disposedand a plurality of sub-pixels SP defined by the plurality of data linesDL and the plurality of gate lines GL are arranged; a source drivingcircuit SDC configured to drive the plurality of data lines DL; a gatedriving circuit GDC configured to drive the plurality of gate lines GL;a timing controller TCON configured to control the source drivingcircuit SDC and the gate driving circuit GDC; and the like.

On the display panel DISP, a pixel electrode in each sub-pixel SP may bedisposed.

A pixel voltage may be applied to the pixel electrode of each sub-pixelSP.

Further, one common electrode or two or more common electrodes to whicha common voltage is applied may be disposed on the display panel DISP.

The one common electrode is one cylindrical electrode formed on thefront surface of the display panel DISP.

The two or more common electrodes may be regarded as electrodes obtainedby dividing one cylindrical electrode into two or more electrodes. Eachof the two or more common electrodes may have a size larger than thesize of one sub-pixel area.

In each sub-pixel SP, an electric field may be formed by a pixel voltage(which may be a data voltage) applied to the pixel electrode and acommon voltage applied to the common electrode.

The timing controller TCON supplies various driving control signals DCSand GCS to the source driving circuit SDC and the gate driving circuitGDC so as to control the source driving circuit SDC and the gate drivingcircuit GDC.

The timing controller TCON starts scanning according to timingimplemented in each frame, converts input image data input from theoutside to be suitable for a data signal form used in the source drivingcircuit SDC, outputs the converted image data DATA, and controls datadriving at a proper time according to the scanning.

The above-mentioned timing controller TCON receives, from the outside(e.g., a host system), various timing signals including a verticalsynchronous signal Vsync, a horizontal synchronous signal Hsync, aninput data enable (DE) signal, a clock signal CLK, etc. together withinput image data.

In addition to converting the input image data input from the outside tobe suitable for a data signal form used in the source driving circuitSDC and outputting the converted image data, in order to control thesource driving circuit SDC and the gate driving circuit GDC, the timingcontroller TCON receives timing signals such as a vertical synchronoussignal Vsync, a horizontal synchronous signal Hsync, an input DE signal,and a clock signal, generates various control signals, and outputs thecontrol signals to the source driving circuit SDC and the gate drivingcircuit GDC.

For example, in order to control the gate driving circuit GDC, thetiming controller TCON may output various gate control signals GCSincluding a gate start pulse (GSP), a gate shift clock (GSC), a gateoutput enable (GOE) signal, etc.

Here, the GSP controls the operation start timing of one or more gatedriver integrated circuits constituting the gate driving circuit GDC.The GSC is a clock signal commonly input to the one or more gate driverintegrated circuits and controls the shift timing of a scan signal (agate pulse). The GOE signal designates the timing information of the oneor more gate driver integrated circuits.

In addition, in order to control the data driving circuit SDC, thetiming controller TCON may output various data driving control signalsDCS including a source start pulse (SSP), a source sampling clock (SSC),a source output enable signal (SOE), etc.

Here, the SSP controls the data sampling start timing of one or moresource driver integrated circuits constituting the source drivingcircuit SDC. The SSC is a clock signal for controlling the samplingtiming of data in each of the source drive integrated circuits. The SOEcontrols the output timing of the source driving circuit SDC.

The timing controller TCON may be a control device that further performsother control functions including the function of the timing controller.

The timing controller TCON may be implemented as a component separatefrom the source driving circuit SDC, or as an integrated circuit bybeing integrated with the source driving circuit SDC.

The source driving circuit SDC receives the image data DATA input fromthe timing controller TCON and supplies a data voltage to the pluralityof data lines DL so as to drive the plurality of data lines DL. Here,the source driving circuit SDC is also referred to as a data drivingcircuit.

The source driving circuit SDC may be implemented by including one ormore source driver integrated circuits (SDIC).

Each SDIC may include a shift register, a latch circuit, a digital toanalog converter (DAC), an output buffer, etc.

Each SDIC may further include an analog to digital converter (ADC) insome cases.

Each SDIC may be connected to a bonding pad of the display panel DISPthrough a tape automated bonding (TAB) method or a chip-on-glass (COG)method or may be disposed directly on the display panel DISP. In somecases, the SDIC may be disposed by being integrated in the display panelDISP. In addition, each SDIC may be implemented by a chip-on-film (COF)method in which the SDIC is mounted on a film connected to the displaypanel DISP.

The gate driving circuit GDC sequentially supplies scan signals to theplurality of gate lines GL so as to sequentially drive the plurality ofgate lines GL. Here, the gate driving circuit GDC is also referred to asa scan driving circuit.

The gate driving circuit GDC may be implemented to include one or moreGDICs.

Each GDIC may include a shift register, a level shifter, etc.

Each GDIC may be connected to a bonding pad of the display panel DISPthrough the TAB method or the COG method, or may be disposed directly onthe display panel DISP by being implemented in a gate-in-panel (GIP)type. In some cases, each GDIC may be disposed by being integrated inthe display panel DISP. In addition, each GDIC may be implemented in theCOF method, in which the GDIC is mounted on a film connected to thedisplay panel DISP.

The gate driving circuit GDC sequentially supplies a scan signal of anON voltage or an OFF voltage to the plurality of gate lines GL under thecontrol of the timing controller TCON.

When a specific gate line is opened by the gate driving circuit GDC, thesource driving circuit SDC converts image data DATA received from thetiming controller TCON into an analog-type data voltage and supplies thedata voltage to the plurality of data lines DL.

The source driving circuit SDC may be located only on one side (e.g.,the upper side or the lower side) of the display panel DISP, or may belocated on both sides (e.g., the upper side and the lower side) of thedisplay panel DISP depending on a driving method, a panel design method,etc. in some cases.

The gate driving circuit GDC may be located only on one side (e.g., theleft side or the right side) of the display panel DISP, or may belocated on both sides (e.g., the left side and the right side) of thedisplay panel DISP depending on a driving method, a panel design method,etc. in some cases.

Referring to FIG. 2, the touch display device according to embodimentsof the present disclosure may include a touch screen panel TSP, a touchdriving circuit TDC, a micro control unit MCU, etc. in order to providethe touch sensing function.

The touch screen panel TSP may include a plurality of touch electrodesTE and a plurality of signal lines SL electrically connected to theplurality of touch electrodes TE.

For example, one touch electrode TE may be electrically connected to onesignal line SL or two or more signal lines SL through one or morecontact holes or the like.

The touch driving circuit TDC may drive the touch screen panel TSP so asto generate and output sensing data (touch raw data).

For example, the touch driving circuit TDC may supply a touch drivingsignal to all or some of the plurality of touch electrodes TE arrangedin the touch screen panel TSP, and may detect a signal from at least onetouch electrode TE, thereby generating and outputting sensing data(touch raw data).

The touch driving circuit TDC may supply a touch driving signal to oneor more touch electrodes TE through one or more signal lines SL, and maydetect a signal.

The micro control unit MCU may obtain the presence or absence of a touchand/or touch coordinates using sensing data output from the touchdriving circuit TDC.

The touch display device according to embodiments of the presentdisclosure may sense a touch based on self-capacitance, or may sense atouch based on mutual-capacitance. Hereinafter, for the convenience ofexplanation, a description will be made of a case where a touch issensed based on self-capacitance as an example.

The touch screen panel TSP may be manufactured separately from thedisplay panel DISP, and may be bonded to the display panel DISP orembedded in the display panel DISP.

When the touch screen panel TSP is embedded in the display panel DISP,the touch screen panel TSP may be regarded as an assembly of a pluralityof touch electrodes TE and a plurality of signal lines SL.

The touch driving circuit TDC and the micro control unit MCU are twocircuits for touch sensing. The touch driving circuit TDC is alsoreferred to as a first circuit, and the micro control unit MCU is alsoreferred to as a second circuit.

The touch driving circuit TDC and the source driving circuit SDC may beintegrally implemented. In this case, an integrated driving circuitincluding both the touch driving circuit TDC and the source drivingcircuit SDC is also referred to as a first circuit.

FIG. 3 is a diagram illustrating a case where a touch screen panel TSPis embedded in the display panel DISP of the touch display deviceaccording to embodiments of the present disclosure.

When the touch screen panel TSP is embedded in the display panel DISP, aplurality of common electrodes COM disposed on the display panel TSP maybe utilized as a plurality of touch electrodes TE.

Accordingly, a common voltage may be applied to the plurality of commonelectrodes COM for image display, and a touch driving signal may beapplied to all or some of the plurality of common electrodes COM fortouch sensing.

An area of each of the plurality of common electrodes COM may overlap anarea of two or more sub-pixels SP.

That is, the size of the area of one common electrode COM may correspondto the size of the area of two or more sub-pixels SP.

Accordingly, two or more gate lines GL may pass through the area of onecommon electrode COM.

According to the above description, the speed, efficiency, orperformance of touch driving and touch sensitivity may be adjusted byadjusting the size of the common electrodes COM.

FIG. 4 is a diagram illustrating time-divisional driving of the touchdisplay device according to embodiments of the present disclosure, andFIG. 5 is a diagram illustrating time-free driving of the touch displaydevice according to embodiments of the present disclosure.

The touch display device according to embodiments of the presentdisclosure may perform a driving operation in a time-divisional drivingmethod and/or a time-free driving method.

Referring to FIG. 4, when performing the driving operation in thetime-divisional driving method, the touch display device according toembodiments of the present disclosure may perform the display drivingfor providing an image display function and the touch driving forproviding a touch sensing function in the time-divisional displaydriving period and the touch driving period, respectively.

The display driving period and the touch driving period may becontrolled in timing by a touch synchronous signal TSYNC.

During the display driving period, a common voltage VCOM, which is a DCvoltage, may be applied to the plurality of common electrodes COM.

During the touch driving period, a touch driving signal LFD, which is anAC voltage (modulated signal), may be applied to all or some of theplurality of common electrodes COM. At this time, the touch drivingsignal LFD or a signal corresponding thereto may be applied to all orsome of the data lines DL. At this time, the touch driving signal LFD ora signal corresponding thereto may be further applied to all or some ofthe gate lines GL.

Referring to FIG. 5, when performing the driving operation in thetime-free driving method, the touch display device according toembodiments of the present disclosure may simultaneously perform thedisplay driving for providing an image display function and the touchdriving for providing a touch sensing function. Such a time-free drivingmethod is also referred to as a simultaneous driving method.

One frame time may correspond to one active time and one blank time.

When the touch display device according to embodiments of the presentdisclosure performs the driving operation in the time-free driving mode,a data voltage VDATA may be supplied to the data lines DL during theactive time at every frame time. At this time, a common voltage VCOM,which also serves as the touch driving signal LFD, may be supplied tothe plurality of common electrodes COM.

Meanwhile, the touch display device according to embodiments of thepresent disclosure may always perform the driving operation in thetime-divisional driving method, may always perform the driving operationin the time-free driving method, or may perform the driving operationusing both the time-divisional driving method and the time-free drivingmethod.

Hereinafter, a case in which the touch display device according toembodiments of the present disclosure performs the driving operation inthe time-free driving method will be described as an example.

When the touch display device according to embodiments of the presentdisclosure performs the driving operation in the time-free drivingmethod, the plurality of common electrodes COM may be regarded as aplurality of touch electrodes TE, and the common voltage VCOM may beregarded as a touch driving signal LFD.

FIG. 6 is a diagram illustrating asynchronization between a data voltageVDATA and a common voltage VCOM during the time-free driving of thetouch display device according to embodiments of the present disclosure,and FIG. 7 is a diagram illustrating a voltage fluctuation phenomenonoccurring in a common electrode COM according to a state change of thedata voltage VDATA during asynchronization between the data voltageVDATA and the common voltage VCOM.

However, FIG. 7 illustrates a phenomenon in which a voltage fluctuationoccurs in the common voltage COM when a state change occurs in the datavoltage VDATA in the state in which a DC voltage is applied to thecommon electrode COM in order to examine a voltage state fluctuation inthe common electrode COM according to a state change in the data voltageVDATA.

Referring to FIG. 6, during the time-free driving of the touch displaydevice according to embodiments of the present disclosure, the datavoltage VDATA applied to pixel electrodes via the data lines DL forimage display and the common voltage VCOM applied to the commonelectrodes COM for image display and touch sensing may have differentfrequencies and may not be synchronized with each other.

Referring to FIGS. 6 and 7, in the specific pattern of a characteristicinversion method, the data voltage VDATA may undergo a state transitionin which the voltage level greatly changes.

Due to this, as illustrated in FIG. 7, the common electrode COM to whichthe DC voltage is applied may undergo a fluctuation in the voltage stateat the time of state change in the data voltage, rather than beingmaintained in the DC voltage state.

When the voltage value of the data voltage VDATA is raised, that is,when the data voltage VDATA rises, the common electrode COM to which theDC voltage has been applied may undergo a fluctuation in the voltagestate in which the voltage instantaneously significantly rises from acorresponding DC voltage and then returns to the corresponding DCvoltage.

When the voltage value of the data voltage VDATA is lowered, that is,when the data voltage VDATA falls, the common electrode COM to which theDC voltage has been applied may undergo a change in voltage state inwhich the voltage instantaneously significantly falls from acorresponding DC voltage and then returns to the corresponding DCvoltage.

As described above, when a voltage state change of the common electrodesCOM acting as the touch electrodes TE according to the state change ofthe data voltage VDATA, a signal detected from the common electrodes COMapplied with the common voltage VOM may also be distorted.

Accordingly, since the touch driving circuit TDC detects the distortedsignal to generate sensing raw data, and the micro control unit MCUdetermines the presence or absence of a touch and/or touch coordinatesusing the sensing raw data generated based on the distorted signal, thepresence or absence of a touch and touch coordinates may not bedetermined or may be erroneously determined. That is, a touch sensingerror may occur or touch sensitivity may be lowered.

As described above, a phenomenon in which a touch sensing error occursor touch sensitivity is lowered due to the occurrence of a voltage statefluctuation in the common electrode COM acting as a touch electrode TEaccording to the state change in the data voltage VDATA is called aDisplay Touch Crosstalk (DTX).

FIG. 8 is a diagram exemplifying an image pattern generating a displaytouch crosstalk according to a voltage fluctuation phenomenon at acommon voltage VCOM in the touch display device according to embodimentsof the present disclosure, and FIG. 9 is a diagram for explaining atouch signal distortion phenomenon caused by a display touch crosstalkaccording to a voltage fluctuation phenomenon at a common voltage VCOMin the touch display device according to embodiments of the presentdisclosure.

The state change of the data voltage VDATA, which may generate a displaytouch crosstalk, and the voltage state change caused thereby in thecommon electrode COM may be caused by a specific display pattern.

For example, when driving an image with an inversion method, the displaytouch crosstalk may occur.

Examples of the inversion method, which may generate the display touchcrosstalk, include a frame inversion method, a line inversion method, acolumn inversion method, a dot inversion method, etc. and there is alsoa Z-Inversion method.

Here, the frame inversion method, the line inversion method, and thecolumn inversion method are capable of reducing the power consumptioncompared to the dot inversion method, but have an image qualitydegradation problem in that a crosstalk phenomenon occurs or adifference in vertical luminance occurs. On the other hand, the dotinversion method is capable of reducing the image quality degradationproblem described above, and thus capable of providing images ofexcellent image quality compared to the frame inversion method, the lineinversion method, and the column inversion method. However, the dotinversion method has a problem in that it consumes too much powercompared to the line inversion method or the column inversion method.

Referring to FIG. 8, the Z-inversion method is an inversion method forsolving the problem of the other inversion methods described above. TheZ-inversion method supplies a data voltage in a column inversion methodto data lines in which transistors and pixel electrodes are arrangedalternately to the left and right.

Referring to FIG. 8, the Z-inversion method has an improved structure ofa column inversion type, and uses a column inversion method in thecircuit driving method, but screen displaying is implemented in the samemanner as the dot inversion method by making the directions oftransistors of the display panel DISP reversed for each line. Inaddition, the Z-inversion method is excellent in image quality by usingthe column inversion method in terms of data and is capable of reducingpower consumption while having an effect similar to that of the dotinversion method in image quality.

When image driving is performed by the Z-inversion method, that is, whena display pattern of the Z-inversion method is displayed, the statechange of the data voltage VDATA may occur more severely compared to theother inversion methods. As a result, the voltage state fluctuation inthe common electrode COM may occur more severely, and thus the displaytouch crosstalk may occur more seriously.

The state change in the data voltage VDATA does not always occurseriously when image driving is performed in the Z-inversion method, butmay occur seriously in a specific display pattern.

In (a), (b), and (c) in FIG. 9, each of the sub-pixel connection marks910, 920, and 930 indicates sub-pixels SP connected to the same dataline DL in the case of the Z-inversion method.

In (a), (b), and (c) in FIG. 9, for the convenience of explanation, adata voltage VDATA corresponding to 255 gradation is represented by 8(positive) and 0 (negative) according to polarity inversion, and a datavoltage VDATA corresponding to the 0 gradation is represented by 3.9 and4.1.

Touch raw data is sensing data obtained in the touch driving circuit TDCand includes sensing values for respective positions. In (a), (b), and(c) in FIG. 9, the graphics for touch raw data represent the magnitudesof sensing values for respective positions on a plane as heights.

Referring to (a) in FIG. 9, for example, when the red sub-pixel columns,the green sub-pixel columns, and the blue sub-pixel columns are allturned ON in order to represent white (255, 255, 255), all the voltagedifferences in the data voltage VDATA supplied to the sub-pixels 910connected to the same data line DL become 0 [V]. That is, no statechange occurs in the data voltage VDATA.

Accordingly, in the touch raw data obtained in the touch driving circuitTDC, a sensing value 912 at a position where a touch actually occurs hasa magnitude different from those of sensing values at other positions.Therefore, in the case of (a) in FIG. 9, a touch can be accuratelysensed.

Referring to (b) in FIG. 9, for example, when only the red sub-pixelcolumns are turned ON and the green sub-pixel columns and the bluesub-pixel columns are turned OFF in order to represent red (255, 0, 0),a voltage difference in the data voltage VDATA supplied to thesub-pixels 920 connected to the same data line DL may become 3.9 [V] or−3.9 [V], or may become 0 [V].

The sum of voltage differences of the data voltage VDATA in one line(one sub-pixel row) becomes 0 [V].

However, in some columns (sub-pixel columns) 921, the data voltage VDATAchanges from 3.9 [V] to −3.9 [V] or from −3.9 [V] to 3.9 [V].

That is, in some columns (sub-pixel columns) 921, the voltage statechange width in the data voltage VDATA is 7.8 [V], and thus the voltagestate change of the data voltage VDATA occurs very much.

Accordingly, in the touch raw data obtained in the touch driving circuitTDC, a sensing value 922 at a position where a touch actually occurs hasa magnitude similar to those of sensing values at other positions.Therefore, in the case of (b) in FIG. 9, a touch cannot be sensed atsome column positions.

Referring to (c) in FIG. 9, for example, when the red sub-pixel columnsare turned ON, the green sub-pixel columns are turned OFF, and the bluesub-pixel columns are turned ON (255, 0, 255) or when the red sub-pixelcolumns are turned OFF, the green sub-pixel columns are turned ON, andthe blue sub-pixel columns are turned OFF (0, 255, 0), a voltagedifference in the data voltage VDATA supplied to the sub-pixels 930connected to the same data line DL may become 3.9 [V] or −3.9 [V].

Therefore, in all the columns (sub-pixel columns) 931, the data voltageVDATA is changed from 3.9 [V] to −3.9 [V] or from −3.9 [V] to 3.9 [V].

That is, in all the columns (sub-pixel columns) 931, the voltage statechange width in the data voltage VDATA is 7.8 [V], and thus the voltagestate change of the data voltage VDATA occurs very much.

In addition, in the example of (c) in FIG. 9, the sum of voltagedifferences of the data voltage VDATA in one line (one sub-pixel row)becomes 23.4 [V] or −23.4 [V].

Therefore, the sum of voltage differences in the data voltage VDATAbetween the lines may be greatly changed from 23.4 [V] to −23.4 [V].This means that the voltage state of the common voltage VCOM applied tothe common electrode COM greatly fluctuates.

Accordingly, in the touch raw data obtained in the touch driving circuitTDC, a sensing value 932 at a position where a touch actually occurs hasa magnitude indistinguishably similar to those of sensing values atother positions. Therefore, in the case of (a) in FIG. 9, a touch cannotbe sensed.

As described above, the voltage state fluctuation of the commonelectrode COM corresponding to the touch electrode TE occurs accordingto the state change of the data voltage VDATA. This means that thecommon electrode COM corresponding to the touch electrode TE is affectedby the data line DL.

As a result, the touch sensitivity may be deteriorated or a displaytouch crosstalk (DTX) may occur.

Therefore, embodiments of the present disclosure are capable ofproviding a driving method capable of eliminating a display touchcrosstalk without deteriorating the touch sensitivity even if thevoltage state fluctuation of the data voltage in a common electrode COMcorresponding to a touch electrode TE occurs according to the statechange of a data voltage VDATA in a data line DL.

In other words, embodiments of the present disclosure are capable ofproviding a driving method capable of minimizing the influence of acommon electrode COM corresponding to a touch electrode TE by a dataline DL.

FIGS. 10 and 11 are diagrams illustrating synchronization between a datavoltage VDATA and a common voltage VCOM during time-free driving of thetouch display device according to embodiments of the present disclosure.

When the touch display device according to embodiments of the presentdisclosure performs the driving operation in the time-free driving mode,during an active time for each frame time, the source driving circuitSDC may supply a data voltage VDATA to the plurality of data lines DL,and the touch driving circuit TDC may supply a common voltage VCOM tothe plurality of common electrodes COM.

The plurality of common electrodes COM are display driving-relatedelectrodes that correspond to pixel electrodes to form an electricfield, and are also touch electrodes TE for touch sensing.

Therefore, the common voltage VCOM applied to the plurality of commonelectrodes COM is a display driving voltage and is also a touch drivingsignal LFD.

This common voltage VCOM may be a modulated signal synchronized with adata voltage VDATA or a modulated signal synchronized with a datasynchronous signal SYNCON.

Here, the data synchronous signal SYNCON may be a signal synchronizedwith the data voltage VDATA.

Meanwhile, the touch driving circuit TDC may detect a touch sensingsignal from at least one of the plurality of common electrodes COM, andmay generate and output sensing data (touch raw data) based on thedetected signal.

The micro control unit MCU may receive the sensing data (touch row data)from the touch driving circuit TDC, and may determine the presence orabsence of a touch and/or touch coordinates using the received sensingdata.

Meanwhile, the source driving circuit SDC may be implemented with onesource driving integrated circuit or two or more source drivingintegrated circuits. The touch driving circuit TDC may be implementedwith one touch driving integrated circuit or two or more touch drivingintegrated circuits.

In addition, the source driving integrated circuits implementing thesource driving circuit SDC and the touch driving integrated circuitsimplementing the touch driving circuit TDC may be combined, therebybeing implemented as a combined driving integrated circuit.

That is, the touch display device according to embodiments of thepresent disclosure may include one or more combined driving integratedcircuits, and each combined driving integrated circuit may include asource driving integrated circuit and a touch driving integratedcircuit.

As described above, the common voltage VCOM, which may be the touchdriving signal LFD, is synchronized with the data voltage VDATA or thedata synchronous signal SYNCON. Thus, even if the voltage state of thecommon electrode COM corresponding to the touch electrode TE changes dueto the state change of the data voltage VDATA in the data line DL, thetouch sensitivity is not deteriorated and the display touch crosstalkcan be eliminated. That is, the influence of the data line DL on thecommon electrode COM corresponding to the touch electrode TE can beminimized.

Referring to FIG. 11, the common voltage VCOM, which is a touch drivingsignal LFD, may be a modulated signal, of which the voltage levelswings.

The common voltage VCOM is an AC voltage signal, of which the voltagelevel changes, and is a pulse signal including a plurality of pulses.

The common voltage VCOM may be a modulated signal obtained by changingthe width, amplitude, phase, or the like of the pulse thereof.

For example, the common voltage VCOM may be one of a pulse amplitudemodulation (PAM) signal, a pulse width modulation (PWM) signal, a pulseposition modulation (PPM) signal, a pulse frequency modulation (PFM)signal, etc.

In the following description, it is assumed that the common voltage VCOMis a PWM signal.

Referring to FIG. 11, the common voltage VCOM may be primarily subjectedto a voltage level change (in FIG. 11, from a low level to a high level)after a predetermined delay time T1 at a first state change point of thedata voltage VDATA or the data synchronous signal SYNCON.

Here, at the first state change point, the data voltage VDATA may bechanged from a first level (e.g., the low level) to a second level(e.g., the high level), and the data synchronous signal SYNCON may bechanged from a second level (e.g., the high level) to a first level(e.g., the low level).

Referring to FIG. 11, the common voltage VCOM may be subjected to avoltage level change after a predetermined delay time T1 from a firststate change point of the data voltage VDATA or the data synchronoussignal SYNCON. Thereafter, the voltage level is secondarily changed (inFIG. 11, from the high level to the low level) again at a second statechange point of the data voltage VDATA or the data synchronous signalSYNCON or a point that is earlier than the second state change point bya predetermined control time T2 (T2 is 0 or larger).

Here, at the second state change point, the data voltage VDATA ischanged from the second level (e.g., the high level) to the first level(e.g., the low level), and the data synchronous signal SYNCON is changedfrom the second level (e.g., the high level) to the first level (e.g.,the low level).

According to the above description, since the high level voltage of thetouch driving signal LFD corresponding to the common voltage VCOM isapplied to the common electrode COM by avoiding a period in which anunnecessary voltage fluctuation (e.g., an instantaneous peak voltage)occurs in the common electrode COM in accordance with the state change(low level↔high level) of the data voltage VDATA, it is possible toprevent touch sensitivity from being deteriorated due to the statechange of the data voltage VDATA.

As described above, while the common voltage VCOM, which is a modulatedsignal synchronized with the data voltage VDATA or a modulated signalsynchronized with the data synchronous signal SYNCON synchronized withthe data voltage VDATA, is supplied to the plurality of commonelectrodes COM, an image displayed through the display panel DISP may bein an inversion-type display pattern.

As described above, in the display pattern in which display touchcrosstalk is likely to occur, occurrence of the display touch crosstalkcan be prevented through synchronization between the data voltage VDATAand the common voltage VCOM.

FIG. 12A is a diagram for explaining signal control of a common voltageVCOM during time-free driving of the touch display device according toembodiments of the present disclosure.

Referring to FIG. 12A, during the time-free driving, (1) the commonvoltage VCOM serving as a load-free driving signal is primarilysubjected to a voltage level change (e.g., changed from the low level tothe high level) after a predetermined delay time T1 from a first statechange point a of the data voltage VDATA or the data synchronous signalSYNCON, (2) the changed voltage level (e.g., the high level) ismaintained for a predetermined time W, and (3) the voltage level issecondarily changed (e.g., changed from the high level to the lowerlevel) at a point earlier by a predetermined control time T2 than asecond state change point b of the data voltage VDATA or the datasynchronous signal SYNCON.

Here, in the common voltage VCOM, the time W during which the high levelis maintained corresponds to the pulse width of the common voltage VCOM.The pulse width W of the common voltage VCOM corresponds to the touchsensing time (touch driving time).

Referring to the signal waveform relationship between the datasynchronous signal SYNCON/data voltage VDATA and the common voltageVCOM, the delay time T1 associated with the primary voltage level change(e.g., the low level→the high level) when the voltage level of thecommon voltage VCOM is changed by being synchronized with the datasynchronous signal SYNCON or the data voltage VDATA may be constant.

As described above, as the delay time T1 associated with the primacyvoltage level change of the common voltage VCOM is constant, the commonvoltage VCOM may be a modulated signal having a constant frequency.

Referring to the signal waveform relationship between the datasynchronous signal SYNCON/data voltage VDATA and the common voltageVCOM, the delay time T2 associated with the secondary voltage levelchange (e.g., the high level→the low level) may be variable.

The control time T2 associated with the secondary voltage level changeof the common voltage VCOM corresponds to the time in which the pulsewidth W of the common voltage VCOM can be controlled.

As the control time T2 varies, the pulse width W of the common voltageVCOM may be variable. Here, the pulse width W of the common voltage VCOMis a time length of a high-level interval, which may mean a touchsensing time (touch driving time). The variation of the pulse width Wmay affect the touch driving (touch sensing).

As described above, as the pulse width W of the common voltage VCOMvaries, the common voltage VCOM may have a constant frequency and a dutycycle or a duty ratio thereof may be variable.

Here, the duty cycle of the common voltage VCOM is the ratio of a touchsensing ON time W relative to one period of the common voltage VCOM(=the touch sensing ON time W+a touch sensing OFF time T1+T2). The dutyratio may mean a ratio of the touch sensing ON time W relative to thetouch sensing OFF time T1+T2.

Referring to FIG. 12A, the pulse width W of the common voltage VCOM maybe widened to a point b.

Meanwhile, in the touch display device, various kinds of noise mayoccur. In order to normally perform the display driving and the touchdriving without being affected by such noise, it may be helpful to varythe frequency of the common voltage VCOM in the form of a modulationsignal (e.g., PWM).

However, in the case of the time-free driving method in which thedisplay driving and the touch driving are simultaneously performed, itis necessary that the common voltage VCOM is synchronized with the datavoltage VDATA or the data synchronous signal SYNCON. In this case, thereis a limit in the frequency variation of the common voltage VCOM.

Therefore, as described above, varying the duty cycle or the duty ratioof the common voltage VCOM while maintaining the frequency of the commonvoltage VCOM enables noise avoidance, thereby improving displayperformance and touch performance.

Taking this into consideration, the adjustment of the duty cycle or theduty ratio of the common voltage VCOM through the variation of the pulsewidth W of the common voltage VCOM may be adaptively adjusted accordingto the noise level.

The noise level may be evaluated based on the magnitude of a signalmeasured at a touch electrode TE of the display panel DISP.

For example, the touch display device may store a reference magnitude ofa signal measured by a touch electrode TE in the absence of a touch inadvance, sense the magnitude of a size at the noise in the absence of atouch in order to evaluate the current noise level, compare themagnitude of the signal sensed thereby with the stored referencemagnitude, and evaluate the noise level according to the degree of adifference value obtained through the comparison.

For example, the touch may evaluate that the larger the differencevalue, the higher the noise level of the touch display device. The touchdisplay device may increase the change amount of the duty cycle or theduty ratio of the common voltage VCOM as the evaluated noise levelincreases and may change the duty cycle or duty ratio of the commonvoltage VCOM more frequently when the noise level changes frequently.

FIG. 12B is a view illustrating examples of a display drive controlsignal that may be utilized as a data synchronous signal SYNCON forsynchronizing a common voltage VCOM with a data voltage VDATA in thetouch display device according to embodiments of the present disclosure.

Since the touch display device according to embodiments of the presentdisclosure performs the driving operation in the time-free drivingmethod, the common voltage VCOM is a display driving-related voltagecorresponding to a pixel voltage, and is also a touch driving signal LFDfor touch sensing.

This common voltage VCOM is synchronized with the data voltage VDATA.

As a result, the common voltage VCOM is changed in voltage level whileavoiding the timing at which the voltage value is greatly changed at thedata voltage VDATA.

For this purpose, the voltage level of the common voltage VCOM may swingbased on the voltage state change timing of the data voltage VDATA.

Unlike this, the voltage level of the common voltage VCOM may swingbased on a signal SYNCON other than the data voltage VDATA, that is, adata synchronous signal SYNCON that is synchronized with the datavoltage VDATA.

The data synchronous signal SYNCON is a signal synchronized with thedata voltage VDATA and may be a dedicated control signal for controllingthe voltage level change timing of the common voltage VCOM.

Unlike this, the data synchronous signal SYNCON may utilize an internaloperation control signal for a display driving control as a controlsignal for controlling the voltage level change timing of the commonvoltage VCOM.

The internal operation control signal for the display driving controlhas already been synchronized with the voltage state change timing ofthe data voltage VDATA.

For example, the internal operation control signal used as the datasynchronous signal SYNCON may be a data driving control signal DCSsupplied from the timing controller TCON to the source driving circuitSDC.

For example, the data driving control signal DCS may include a sourcestart pulse (SSP), a source sampling clock (SSC), a source output enablesignal (SOE), etc.

As another example, the internal operation control signal used as thedata synchronous signal SYNCON may be a gate driving control signal GCSsupplied from the timing controller TCON to the gate driving circuitGDC.

For example, the gate drive control signal GCS may be a gate start pulse(GSP), a gate shift clock (GSC), a gate output enable signal (GOE), agate clock signal (GCLK), a gate pulse modulation control signal(GPMCS), or the like. Here, the GPMCS is a signal for controlling thegate pulse modulation (GPM). For example, the GPMCS may include MCLK orFLK The GPM is a modulation technique that modifies the gate pulses.

As illustrated in FIG. 12B, the delay time T1 for avoiding the statechange timing of the data voltage VDATA may vary depending on the typeof the data synchronous signal SYNCON.

As described above, by using an existing internal operation controlsignal for a display driving control as the data synchronous signalSYNCON, there is an advantage in that no separate control signal may beused.

Hereinafter, a ground modulation function and a method of synchronizinga common voltage VCOM, which is a touch driving signal LFD, with a datavoltage VDATA or a data synchronous signal SYNCON using the groundmodulation function will be described.

FIG. 13 is a diagram illustrating two ground voltages GND A and GND Band a ground modulation circuit GMC for using the ground voltages in thetouch display device according to embodiments of the present disclosure.FIG. 14 is a diagram illustrating the ground modulation circuit GMC inthe touch display device according to embodiments of the presentdisclosure. FIG. 15 is a diagram illustrating a configuration forperforming a ground modulation function for data synchronization of acommon voltage VCOM which is a touch driving signal LFD in the touchdisplay device according to embodiments of the present disclosure.

The touch display device according to embodiments of the presentdisclosure may utilize two different ground voltages GND A and GND B.

Various configurations included in the touch display device according toembodiments of the present disclosure may be grounded to one or both oftwo ground voltages GND A and GND B.

Accordingly, the touch display device may include configurationsgrounded to the first ground voltage GND A corresponding to the groundvoltage GND, which is a DC voltage, configurations grounded to thesecond ground voltage GND B, which is an AC voltage, and configurationsboth the first ground voltage GND A and the second ground voltage GND B.

A micro control unit MCU, a timing control unit TCON, etc. may bepresent in a first ground voltage area (GND A area) which is an areagrounded to the first ground voltage GND A. That is, the micro controlunit MCU, the timing control unit TCON, and the like may be grounded tothe first ground voltage GND A, which is a DC voltage.

A display panel DISP, a gate drive circuit GDC, a level shifter, etc.may be present in a second ground voltage area (GND B Area) which is anarea grounded to the second ground voltage GND B. That is, the displaypanel DISP, the gate drive circuit GDC, the level shifter, etc. may begrounded to the second ground voltage GND B, which is an AC voltage.

The source driving circuit SDC transmits a signal to the display panelDISP grounded to the second ground voltage GND B, which is an ACvoltage, and also transmits a signal to the timing control unit TCONgrounded to the first ground voltage GND A, which is a DC voltage. Thus,the source driving circuit SDC should be grounded to both the firstground voltage GND A, which is a DC voltage and the second groundvoltage GND B, which is an AC voltage.

In addition, the touch driving circuit TDC transmits a signal to thedisplay panel DISP grounded to the second ground voltage GND B, which isan AC voltage, and also transmits a signal to the micro control unit MCUgrounded to the first ground voltage GND A, which is a DC voltage. Thus,the touch driving circuit TDC should be grounded to both the firstground voltage GND A, which is a DC voltage and the second groundvoltage GND B, which is an AC voltage.

According to the above description, it is possible to efficiently usetwo ground voltages GND A and GND B in a single touch display device.Through this, it is possible to simultaneously perform image display andtouch sensing by performing time-free driving efficiently.

Furthermore, the voltages applied to various electrodes and wiresarranged on the display panel DISP swing together with the second groundvoltage GND B, whereby the common electrode COM, which is a touchelectrode TE, does not form unnecessary parasitic capacitance with otherelectrodes or wires, so that touch sensitivity can be further improved.

Referring to FIGS. 13 to 15, the touch display device according toembodiments of the present disclosure may further include a pulsemodulation circuit PMC, a ground modulation circuit GMC, etc. in orderto generate the second ground voltage GND B, which is an AC voltage.

The pulse modulation circuit PMC may output a pulse modulation signal(e.g., PWM) to the ground modulation circuit GMC.

The pulse modulation circuit PMC may be included outside or inside themicro control unit MCU.

The ground modulation circuit GMC may output the second ground voltageGND B which is a ground voltage modulated in accordance with the pulsemodulation signal (e.g., PWM) input from the pulse modulation circuitPMC.

When generating the second ground voltage GND B based on the pulsemodulation signal PWM, the ground modulation circuit GMC may generatethe second ground voltage GND B so as to correspond to the pulsemodulation signal PWM in frequency and phase.

However, when generating the second ground voltage GND B based on thepulse modulation signal PWM, the ground modulation circuit GMC maygenerate the second ground voltage GND B having a desired amplitude Vbregardless of the amplitude Va of the pulse modulation signal PWM.

Therefore, the amplitude Vb of the second ground voltage GND B may beequal to, less than, or greater than the amplitude Va of the pulsemodulation signal PWM.

The ground modulation circuit GMC may include a voltage level changecircuit such as a level shifter.

When generating the second ground voltage GND B based on the pulsemodulation signal PWM, such a ground modulation circuit GMC may generatethe second ground voltage GND B based on the voltage level of the firstground voltage GND A, which is a DC voltage.

In addition, the second ground voltage GND B generated by the groundmodulation circuit GMC may look like a modulated signal, which is notconstant in voltage and has two or more voltage levels when viewed withreference to the first ground voltage GND A.

The common voltage VCOM applied to the common electrodes COM, which alsoserve as the touch electrodes TE, may correspond to the second groundvoltage GND B, which is a modulated ground voltage output from theground modulation circuit GMC.

For example, the common voltage VCOM may have a frequency and a phasecorresponding to the frequency and the phase of the second groundvoltage GND B.

Since the second ground voltage GND B in the form of an AC signal isgenerated using the aforementioned ground modulation circuit GMC and thegenerated second ground voltage GND B corresponds to the common voltageVCOM, the common voltage VCOM applied to the common electrodes COM mayswing like the modulated second ground voltage GND B.

Meanwhile, the common voltage VCOM output from a circuit such as thesource driving circuit SDC may be in the form of a DC voltage. However,since the display panel DISP is grounded to the second ground voltageGND B, the common voltage VCOM applied to the common electrodes COMarranged in the second ground voltage GND B may also show a swingingvoltage state like the second ground voltage GND B.

In this case, the common voltage VCOM applied to the common electrodesCOM may have a signal waveform which is the same as or similar to thatof the second ground voltage GND B.

In addition, the common voltage VCOM applied to the common voltages COMmay look like a modulated signal, which is not constant in voltage andhas two or more voltage levels when viewed with reference to the firstground voltage GND A.

Referring to FIGS. 14 and 15, the ground modulation circuit GMC mayreceive an input of one or more power supply voltages VCC and VSS, afirst ground voltage GND A, which is a ground voltage GND as a DCvoltage, and a pulse modulation signal PWM.

The ground modulation circuit GMC may output one or more modulationpower supply voltages VCC_M and VSS_M modulated in accordance with thepulse modulation signal PWM.

The ground modulation circuit GMC may output a second ground voltage GNDB which is a ground voltage GND M modulated in accordance with the pulsemodulation signal PWM.

The one or more modulation power supply voltages VCC_M, VSS_M and thesecond ground voltage GND B may correspond to the pulse modulationsignal PWM.

For example, since the one or more modulation power supply voltagesVCC_M and VSS_M and the second ground voltage GND B are generated on thebasis of the pulse modulation signal PWM, the modulation power supplyvoltages VCC_M and VSS_M and the second ground voltage GND B may have afrequency and a phase, which are the same as those of the frequency andphase of the pulse modulation signal PWM, or a frequency and a phase,which are increased or decreased in a predetermined ratio to those ofthe pulse modulation signal PWM.

The ground modulation circuit GMC may output one or more modulationpower supply voltages VCC_M and VSS_M and a second ground voltage GND Bto the source driving circuit SDC and/or the touch driving circuit TDC,or to an integrated driving circuit SRIC, which is implemented byintegrating the driving circuit SDC and the touch driving circuit TDC.

According to the above description, the ground modulation circuit GMCmay not only generate and supply the second ground voltage GND B in theform of an AC voltage using the pulse modulation signal PWM, but alsogenerate and supply one or more modulation power supply voltages VCC_Mand VSS_M for use in source driving and/or touch driving.

Meanwhile, referring to FIG. 15, the timing controller TCON may output adata synchronous signal SYNCON to the pulse modulation circuit PMC.

Thus, the pulse modulation circuit PMC may generate and output a pulsemodulation signal (e.g., PWM) synchronized with the data synchronoussignal SYNCON.

That is, the pulse modulation signal PWM output from the pulsemodulation circuit PMC may be synchronized with the data voltage VDATAor the data synchronous signal SYNCON.

As described above, since the pulse modulation signal PWM used forground modulation is synchronized with the data voltage VDATA or thedata synchronous signal SYNCON, the second ground voltage GND Bmodulated in accordance with the pulse modulation signal PWM may also besynchronized with the data voltage VDATA or the data synchronous signalSYNCON. Thus, the common voltage VCOM, which is applied to the pluralityof common electrodes COM arranged on the display panel DISP grounded tothe second ground voltage GND B and is a touch driving signal LFD, mayswing like the ground voltage GND B so as to be synchronized with thedata voltage VDATA or the data synchronous signal SYNCON.

Meanwhile, referring to FIGS. 13 and 16, the ground modulation circuitGMC may have a power supply separation function for separating the firstground voltage GND A in the form of a DC voltage and the second groundvoltage GND B in the form of an AC voltage.

For this purpose, the ground modulation circuit GMC may include a powersupply separation circuit including at least one of a flyback converter,a flybuck converter, and a transformer.

Therefore, the touch display device according to embodiments of thepresent disclosure may utilize two different ground voltages GND A andGND B as a ground power supply.

FIG. 16 is an exemplary diagram of a power supply separation circuit inthe touch display device according to embodiments of the presentdisclosure.

FIG. 16 is an example of a power source separation circuit, which is aflyback converter.

The flyback converter may include a transformer TRANS, a switch SW, adiode D, an output capacitor C, etc.

The switch SW may be electrically connected between the primary windingof the transformer TRANS and the first ground voltage GND A. An outputvoltage Vo and the second ground voltage GND B are applied to both endsof the output capacitor C.

When the switch SW is closed, the primacy side of the transformer TRANSis directly connected to an input voltage source Vi. The primary currentand magnetic fluxes of the transformer TRANS increase. Since a voltagehaving a polarity opposite the polarity of the primary winding isinduced in the secondary winding of the transformer TRANS, the voltageinduced in the secondary winding becomes a negative voltage. Thus, thediode D is reverse-biased. That is, the diode D is cut off. Therefore,no current flows in the secondary winding and current flows only in theprimary winding such that energy is accumulated in the transformerTRANS. In addition, the output capacitor C is capable of supplyingenergy to a power management circuit PMIC, which is the output load.

When the switch SW is opened, the primary current and the magneticfluxes decrease. In the secondary winding, a voltage having the polarityopposite the previous polarity is induced. That is, the secondaryvoltage becomes the positive polarity. As a result, the diode D isforward-biased to be conductive, and current flows in the transformerTRANS. The energy from the transformer TRANS is capable of rechargingthe capacitor C and supplying power to the power management circuitPMIC, which is the output load.

The transformer TRANS is capable of serving not only as a power supplyseparator for isolation between input and output, but also as aninductor of a filter.

The above-mentioned first ground voltage GND A, second ground voltageGND B, and common voltage VCOM will be described once again.

The first ground voltage GND A is in the form of a DC voltagemaintaining a constant voltage, but the second ground voltage GND B maybe a modulated voltage in comparison with the first ground voltage GNDA. That is, the voltage level of the second ground voltage GND B is notmaintained at a constant voltage level in comparison with the firstground voltage GND A, but may be a voltage that is a modulated signal,of which the voltage level changes with time.

Since the second ground voltage GND B is in the form of a modulatedsignal, the common voltage VCOM applied to the display panel DISP mayalso be recognized as being modulated therewith.

That is, the common voltage VCOM may be recognized as being modulatedsuch that the voltage level thereof changes with time in comparison withthe first ground voltage GND A.

However, the common voltage VCOM may be regarded as a DC voltage, ofwhich the voltage level does not change with time, as viewed incomparison with the second ground voltage GND B. That is, the commonvoltage VCOM is a signal, of which the voltage level changes with timeas viewed from the first ground voltage GND A side. However, the commonvoltage VCOM may be a signal, of which the voltage level is constantwithout being changed when viewed from the second ground voltage GND Bside.

FIG. 17 is a flowchart of a method of driving the touch display deviceaccording to embodiments of the present disclosure.

Referring to FIG. 17, a method of driving a touch display deviceaccording to embodiments of the present disclosure includes supplying adata voltage VDATA to a plurality of data lines DL and supplying acommon voltage VCOM to a plurality of common electrodes COM (S1720), anddisplaying an image through a display panel DISP and sensing a touchbased on a signal detected from at least one of the plurality of commonelectrodes COM (S1730).

When the touch display device according to embodiments of the presentdisclosure performs time-free driving (simultaneous driving), theplurality of common electrodes COM may also serve as touch electrodesTE.

Accordingly, the common voltage VCOM is a voltage that forms an electricfield with a pixel voltage for image display, and may also be a touchdriving signal LFD applied to the touch electrodes TE for touch sensing.

In order to prevent a display touch crosstalk caused by a state changeof the data voltage VDATA occurring in a specific display pattern, thecommon voltage VCOM may be a modulation signal (a pulse signal includinga plurality of pulses) synchronized with the data voltage VDATA, or amodulation signal (a pulse signal including a plurality of pulses)synchronized with a data synchronous signal SYNCON, which issynchronized with the data voltage VDATA.

When the driving method described above is used, the common voltageVCOM, which may be the touch driving signal LFD, is synchronized withthe data voltage VDATA or the data synchronous signal SYNCON. Thus, evenif the voltage state of the common electrode COM corresponding to thetouch electrode TE changes due to the state change of the data voltageVDATA in the data line DL, the touch sensitivity is not deteriorated andthe display touch crosstalk can be eliminated. That is, the influence ofthe data line DL on the common electrode COM corresponding to the touchelectrode TE can be minimized.

The display panel DISP may be grounded to the second ground voltage GNDB in the form of an AC signal. Here, the AC signal or the AC voltagedescribed in this specification may include all signals, each of whichhas a voltage inconstant over time, or all the inconstant voltages.Also, the AC signal or the AC voltage may include all signals, each ofwhich has an inconstant voltage having a changing polarity, or theinconstant voltages thereof, and all signals, each of which has aninconstant voltage having an unchanged polarity, or the inconstantvoltages thereof.

Accordingly, before step S1720, the driving method of the touch displaydevice according to embodiments of the present disclosure may furtherinclude generating the second ground voltage GND B, which is amodulation signal corresponding to a frequency and a phase of the commonvoltage VCOM and is an AC signal (S1710).

As described above, since the second ground voltage GND B is generatedand the display panel DISP is grounded to the second ground voltage GDNB, the common voltage VCOM, which is a DC voltage applied to the commonelectrodes COM arranged on the display panel DISP, swings like thesecond ground voltage GDN B, and thus, the common voltage VCOM becomesan AC signal, which is the same as or similar to the second groundvoltage GDN B.

In step S1710, the second ground voltage GND B is generated insynchronization with the data voltage VDATA or the data synchronoussignal SYNCON.

Accordingly, since the second ground voltage GND B synchronized with thedata voltage VDATA or the data synchronous signal SYNCON is grounded onthe display panel DISP, the common voltage VCOM, which is a DC voltageapplied to the common electrodes COM arranged on the display panel DISP,swings like the second ground voltage GDN B. Thus, the common voltageVCOM is synchronized with the data voltage VDATA or the data synchronoussignal SYNCON like the second ground voltage GDN B.

Embodiments of the present disclosure described above will be brieflysummarized. A touch display device according to embodiments of thepresent disclosure may include: a display panel DISP, on which aplurality of data lines DL and gate lines GL are disposed, a pluralityof sub-pixels SP defined by the plurality of data lines DL and gatelines GL are arranged, and a plurality of common electrodes COM aredisposed; a first circuit (e.g., SRIC) configured to supply a datavoltage VDATA to the plurality of data lines DL, and supply a commonvoltage VCOM, which is a modulation signal synchronized with the datavoltage VDATA or a modulation signal synchronized with a datasynchronous signal SYNCON synchronized with the data voltage VDATA, tothe plurality of common electrodes COM; and a second circuit (e.g., MCU)configured to sense a touch based on a signal detected by the firstcircuit (e.g., SRIC).

The first circuit (e.g., SRIC) may include a source driving circuit SDCand a touch driving circuit TDC.

A driving circuit of a touch display device according to embodiments ofthe present disclosure may include: a first driving circuit (e.g., SDC)configured to supply a data voltage VDTA to a plurality of data linesDL; and a second driving circuit (e.g., TDC) configured to supply acommon voltage VCOM, which is a modulation signal synchronized with thedata voltage VDATA or a modulation signal synchronized with a datasynchronous signal SYNCON synchronized with the data voltage VDATA, to aplurality of common electrodes COM, and detect a signal for touchsensing from at least one of the plurality of common electrodes COM.

A touch display device according to embodiments of the presentdisclosure may include: a display panel DISP, on which a plurality ofdata lines DL and gate lines GL are disposed, a plurality of sub-pixelsSP defined by the plurality of data lines DL and gate lines GL arearranged, and a plurality of common electrodes COM are disposed; a firstcircuit (e.g., SRIC) configured to supply a common voltage VCOM to aplurality of common electrodes COM and detect a signal from at least oneof the plurality of common electrodes COM; and a second circuit (e.g.,MCU) configured to sense a touch based on the detected signal while animage is displayed through the display panel DISP.

The voltage level of the common voltage VCOM may change at the timingwhen the voltage level of the data voltage VDATA is unchanged.

A touch display device according to embodiments of the presentdisclosure may include: a display panel DISP, on which a plurality ofdata lines DL and gate lines GL are disposed, a plurality of sub-pixelsSP defined by the plurality of data lines DL and gate lines GL arearranged, and a plurality of touch electrodes TE are disposed; a firstcircuit (e.g., SRIC) configured to supply a data voltage VDATA to theplurality of data lines DL, supply a touch driving signal LFD to theplurality of touch electrodes TE, and detect a signal from at least oneof the plurality of touch electrodes TE; and a second circuit (e.g.,MCU) configured to sense a touch based on the detected signal while animage is displayed through the display panel DISP.

The display panel DISP may be grounded to a second ground voltage GNN Bwhich has a predetermined frequency and has been modulated.

The touch driving signal LFD is a modulation signal having a swingingvoltage level, and may have a frequency and a phase corresponding tothose of the modulated second ground voltage GND B.

The touch driving signal LFD may be the same signal as the second groundvoltage GND B.

The voltage level of the touch driving signal LFD may be changed at thetiming when the voltage level of the data voltage VDATA is unchanged.

According to the above-described embodiments of the present disclosure,it is possible to provide a touch display device, a driving method, anda driving circuit capable of simultaneously performing display drivingand touch driving.

According to the embodiments of the present disclosure, it is possibleto provide a touch display device, a driving method, and a drivingcircuit that prevent touch sensitivity from being affected by displaydriving.

According to the embodiments of the present disclosure, it is possibleto provide a touch display device, a driving method, and a drivingcircuit capable of performing touch sensing without being affected bydata driving.

According to the embodiments of the present disclosure, it is possibleto provide a touch display device, a driving method, and a drivingcircuit capable of preventing touch sensing from being disabled or atouch sensitivity from being deteriorated even if a voltage state of adata voltage is changed.

According to the embodiments of the present disclosure, it is possibleto provide a touch display device, a driving method, and a drivingcircuit capable of preventing touch sensing from being disabled or atouch sensitivity from being deteriorated in a specific display pattern.

According to the embodiments of the present disclosure, it is possibleto provide a touch display device, a driving method, and a drivingcircuit capable of preventing a display touch crosstalk in which atouch-related signal is distorted by display driving even though thedisplay driving and touch driving are simultaneously performed.

The above description and the accompanying drawings provide an exampleof the technical idea of the present disclosure for illustrativepurposes only. Those having ordinary knowledge in the technical field,to which the present disclosure pertains, will appreciate that variousmodifications and changes in form, such as combination, separation,substitution, and change of a configuration, are possible withoutdeparting from the essential features of the present disclosure.Therefore, the embodiments disclosed in the present disclosure areintended to illustrate the scope of the technical idea of the presentdisclosure, and the scope of the present disclosure is not limited bythe embodiment. The scope of the present disclosure shall be construedon the basis of the accompanying claims in such a manner that all of thetechnical ideas included within the scope equivalent to the claimsbelong to the present disclosure.

What is claimed is:
 1. A touch display device comprising: a displaypanel including a plurality of data lines, a plurality of gate lines, aplurality of sub-pixels defined by the plurality of data lines and theplurality of gate lines, and a plurality of common electrodes; a firstcircuit configured to supply a data voltage to the plurality of datalines, supply a common voltage that alternates between a first commonvoltage level and a second common voltage level that is greater than thefirst common voltage level to the plurality of common electrodes, anddetect a signal from at least one of the plurality of common electrodes,wherein the common voltage changes from the first common voltage levelto the second common voltage level at a predetermined time after thedata voltage changes from a first data voltage level to a second datavoltage level that is greater than the first data voltage level or at apredetermined time after a data synchronous signal that is synchronizedwith the data voltage changes from a first signal level to a secondsignal level that is less than the first signal level; and a secondcircuit configured to sense a touch based on a signal detected by thefirst circuit.
 2. The touch display device of claim 1, wherein thecommon voltage changes from the second common voltage level to the firstcommon voltage level a predetermined time before the data voltagechanges from the second data voltage level to the first data voltagelevel or a predetermined time before the data synchronous signal changesfrom the second signal level to the first signal level.
 3. The touchdisplay device of claim 2, wherein the predetermined time is constantand a duration of the predetermined time is variable.
 4. The touchdisplay device of claim 1, wherein the common voltage has a constantfrequency and a variable duty cycle or duty ratio.
 5. The touch displaydevice of claim 1, further comprising: a pulse modulation circuitconfigured to output a pulse modulation signal; and a ground modulationsignal configured to output a ground voltage modulated in accordancewith the pulse modulation signal, wherein the common voltage is based onthe modulated ground voltage.
 6. The touch display device of claim 5,wherein the common voltage has a frequency and a phase corresponding toa frequency and a phase of the modulated ground voltage.
 7. The touchdisplay device of claim 5, wherein the pulse modulation signal issynchronized with the data voltage or the data synchronous signal. 8.The touch display device of claim 5, wherein the ground modulationcircuit comprises a power supply separation circuit configured togenerate a first ground voltage and a second ground voltage, wherein thefirst ground voltage has a direct current (DC) voltage, and the secondground voltage has an alternating current (AC) voltage.
 9. The touchdisplay device of claim 5, wherein the ground modulation circuitreceives an input of at least one power supply voltage, a first groundvoltage having a direct current (DC) voltage, or the pulse modulationsignal, and the ground modulation circuit outputs at least onemodulation power supply voltage modulated in accordance with the pulsemodulation signal and outputs a second ground voltage that is modulatedin accordance with the pulse modulation signal.
 10. The touch displaydevice of claim 9, wherein the ground modulation circuit outputs the atleast one modulation power supply voltage to the first circuit.
 11. Thetouch display device of claim 1, wherein the second circuit is groundedto a first ground voltage having a direct current (DC) voltage, and thedisplay panel is grounded to a second ground voltage having analternating current (AC) voltage.
 12. The touch display device of claim1, wherein the first circuit is grounded to both a first ground voltagehaving a direct current (DC) voltage, and a second ground voltage havingan alternating (AC) voltage.
 13. The touch display device of claim 1,wherein the data synchronous signal is a data driving control signalsupplied to the first circuit by a timing controller.
 14. The touchdisplay device of claim 1, wherein the data synchronous signal is a gatedriving control signal supplied to a gate driving circuit by a timingcontroller.
 15. The touch display device of claim 1, wherein an area ofeach of the plurality of common electrodes overlaps two or moresub-pixel areas.
 16. The touch display device of claim 1, wherein animage displayed through the display panel while the common voltage issupplied to the plurality of common electrodes is an inversion-typedisplay pattern.
 17. A method of driving a touch display devicecomprising a display panel that includes a plurality of data lines, aplurality of gate lines, a plurality of sub-pixels defined by theplurality of data lines and the plurality of gate lines, and a pluralityof common electrodes, the method comprising: supplying a data voltage tothe plurality of data lines; supplying a common voltage that alternatesbetween a first common voltage level and a second common voltage levelthat is greater than the first common voltage level to the plurality ofcommon electrodes, wherein the common voltage changes from the firstcommon voltage level to the second common voltage level at apredetermined time after the data voltage changes from a first datavoltage level to a second data voltage level that is greater than thefirst data voltage level or at a predetermined time after a datasynchronous signal that is synchronized with the data voltage changesfrom a first signal level to a second signal level that is less than thefirst signal level; and displaying an image through the display paneland sensing a touch based on a signal detected from at least one of theplurality of common electrodes.
 18. The method of claim 17, furthercomprising: generating a ground voltage having a frequency and a phasethat corresponds to a frequency and a phase of the common voltage beforethe data voltage and the common voltage are supplied.
 19. The method ofclaim 18, wherein the common voltage has a constant frequency and avariable duty cycle or duty ratio.
 20. A driving circuit of a touchdisplay device comprising a display panel including plurality of datalines, a plurality of gate lines, a plurality of sub-pixels defined bythe plurality of data lines and the plurality of gate lines, and aplurality of common electrodes, the driving circuit comprising: a firstdriving circuit configured to supply a data voltage to the plurality ofdata lines; and a second driving circuit configured to supply a commonvoltage that alternates between a first common voltage level and asecond common voltage level that is greater than the first commonvoltage level to the plurality of common electrodes, and detect a signalfor touch sensing from at least one of the plurality of commonelectrodes; wherein the common voltage changes from the first commonvoltage level to the second common voltage level a predetermined timeafter the data voltage changes from a first data voltage level to asecond data voltage level that is greater than the first data voltagelevel or at a predetermined time after a data synchronous signal that issynchronized with the data voltage changes from a first signal level toa second signal level that is less than the first signal level.